Soil and Water

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Soil and Water
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SOILS

• Texture of sand, silt, and clay
• Amount of water stored in soil

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Texture
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SOILS

• Structure arrangement of particles
• Amount of pore space

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SOIL MOISTURE

• Gravitational water drains through soil by
  gravity

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SOIL MOISTURE

• Field capacity soil moisture after gravitational
  water has been allowed to drain (24 hours)

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SOIL MOISTURE

• Permanent wilting point plants can no longer
  extract moisture

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INTAKE RATE

• How quickly water enters the soil
• Slows down as soil becomes wet
• Cycle and Soak programs

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AVAILABLE WATER HOLDING CAPACITY (AW)

• Amount of soil moisture between field capacity
  and permanent wilting point

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EVAPOTRANSPIRATION (ET)

• Total water loss from evaporation and
  transpiration
• Evaporation loss of water from soil surface
• Transpiration loss of water through plant for
  cooling

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EVAPOTRANSPIRATION (ET)

• ET0 is a reference ET, locally or regionally

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• http//www.clemson.edu/public/rec/edisto/facilitie
  s/
• http//fawn.ifas.ufl.edu/
• http//edis.ifas.ufl.edu/ae455

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PLANT REQUIREMENTS

• Plant water needs vary
• Root depth and physiology
• Hydrozones separating irrigation zones by plants
• Turf, flowers, tree and shrub beds

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IRRIGATION SCHEDULING

• 1. HOW MUCH WATER IS LOST PER DAY?
• Loss of water through ET (inches per day)
• WATER LOSS ET

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IRRIGATION SCHEDULING

• 2. HOW MUCH WATER CAN BE LOST BEFORE REPLACING IT
  WITH IRRIGATION?
• The READILY AVAILABLE WATER!

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IRRIGATION SCHEDULING

• READILY AVAILABLE WATER
• Dont wait until all the water is gone from the
  soil!
• Readily Available Water
• Root Water x Management Allowed Depletion

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IRRIGATION SCHEDULING

• Root Water
• Root Depth x Available Water Holding Capacity
• Root depth of plants to be irrigated
• Available water holding capacity of soil
• Sand
• Silt
• Clay

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IRRIGATION SCHEDULING

• Management Allowed Depletion
• The amount of water allowed to deplete from soil
  before its replaced
• Use table

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IRRIGATION SCHEDULING

• 3. HOW OFTEN SHOULD YOU IRRIGATE? (Days)
• Readily Available Water ET
• Round the days up or down to a whole number

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IRRIGATION SCHEDULING

• 4. HOW MUCH SHOULD YOU IRRIGATE?
• Days X ET

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IRRIGATION SCHEDULING

• 5. HOW MANY MINUTES DO YOU RUN IRRIGATION?
• (Irrigation Amount Precipitation Rate) X 60
• Precipitation rate how fast water is being
  applied
• Inches / hour